There are a variety of physical light emitting mechanisms employed in display technology and suitable techniques for accessing data to be displayed in these technologies have been developed. For example U.S. Pat. No. 3,761,897 to Tech (assigned to the instant assignee) describes a gas cell memory system with electrical readout. The accessing technique described in that patent electrically determines the latched state of any one cell to selectively write or erase it. A pulse equal to or greater than the sustain level is applied to a selected line on one axis while all lines on the other axis are sensed. The presence of the pulse in the sensed line indicates a binary one or lighted cell and the absence of pulse indicates a binary zero or unlit cell. In this manner, the state of individual cells may be determined electrically. However, there is a significant problem with applying this pulse magnitude technique to reading the stored state in electroluminescent panel displays. The change in impedance between the lit and unlit cell in an electroluminescent panel display is so small that the corresponding change in the magnitude of interrogation pulses propagated through such a cell is indistinguishable from background noise and leakage.